The present invention relates to a button battery holder adapted to be mounted into an electronic equipment, for example, for holding a button battery, and more particularly to an improvement in such a holder which can prevent incorrect orientation of electrode surfaces of the button battery upon insertion of the button battery into the holder.
Conventionally, various types of button battery holders are known. One example of the known holders is constructed in such a manner that the holder accommodating a button battery is mounted to an electronic equipment in a direction perpendicular to electrode surfaces of the button battery. In this type of holder, an opening formed in the electronic equipment for mounting the holder becomes large to deteriorate an external appearance of the electronic equipment and cause an enlargement in size of the electronic equipment.
To cope with this defect, there has been proposed another type of holder constructed in such a manner that the holder accommodating the button battery is inserted and mounted into the electronic equipment in a direction parallel to the electrode surfaces of the button battery. In this improved type of holder, a holder insert hole and a holder mounting portion formed in the electronic equipment can be made small.
FIGS. 7 and 8A to 8C show an example of such a conventional button battery holder as designated by reference character a.
Referring to FIG. 7, the holder a formed of synthetic resin having a flexibility includes a base portion b integrally formed with a bottom plate portion b.sub.1 and a rear end portion b.sub.2. A pair of right and left parallel arm portions c and c' extend frontwardly from right and left edges of the rear end portion b.sub.2 of the base portion b.
An arcuate wall d projects upwardly from the bottom plate portion b.sub.1 of the base portion b, and right and left edges of the arcuate wall d are connected with inner surfaces of the arm portions c and c', respectively.
An arcuate wall e having an elasticity is disposed in opposed relationship to the arcuate wall d, and right and left edges of the arcuate wall e are connected with the inner surfaces of the arm portions c and c', respectively. Accordingly, a pair of right and left intermediate portions c.sub.1 and c'.sub.1 are formed between both the right edges of the arcuate walls d and e and between both the left edges of the arcuate walls d and e, respectively. Further, a substantially circular accommodating space f for accommodating a button battery l is defined by the two arcuate walls d and e and the intermediate portions c.sub.1 and c'.sub.1 of the arm portions c and c'. An inner diameter of the accommodating space f is set to be substantially equal to an outer diameter of the button battery l. A pair of right and left receiving plates g and g' are formed near the right and left edges of the arcuate wall e so as to project inwardly of the space f from an inner surface of the arcuate wall e at the same level as that of the bottom plate portion b.sub.1 of the base portion b. Further, a pair of right and left holding portions h and h' project inwardly of the space f from the inner surfaces of the intermediate portions c.sub.1 and c'.sub.1 of the arm portions c and c' at the upper edges thereof, respectively.
Further, a pair of right and left pawls i and i' (see FIGS. 8A to 8C) are formed to project from outer surfaces of the arm portions c and c' at front end portions thereof. When the holder a is fully inserted into an electronic equipment (not shown), the pawls i and i' are brought into engagement with a pair of engaging portions (not shown) provided in the electronic equipment, thus providing click lock of the holder a in the electronic equipment.
The button battery l such as a lithium battery is constructed of an outer shell 4 formed by a positive electrode shell 2 and a negative electrode shell 3 electrically insulated from the positive electrode shell 2. A required substance is contained in the outer shell 4.
The positive electrode shell 2 includes a circular flat positive electrode surface 2a and a side wall portion 2b continuing downwardly from an outer circumferential edge of the positive electrode surface 2a and curved inwardly toward an outer circumference of the negative electrode shell 3. The negative electrode shell 3 projects downwardly at a position slightly spaced from an inner circumferential edge of the side wall portion 2b, and includes a circular flat negative electrode surface 3a. Thus, as viewed in side elevation, that is, in a direction parallel to the electrode surfaces 2a and 3a, the button battery l is configured in such a manner that the small-diameter negative electrode shell 3 projects slightly from a lower surface of the large-diameter positive electrode shell 2, and that the side wall portion 2b is curved at its lower portion toward the outer circumference of the negative electrode shell 3.
The button battery l is mounted into the holder a in the following manner.
As shown in FIG. 8A, the positive electrode surface 2a of the button battery l is oriented upwardly, and a first part of the outer circumferential portion of the button battery l is inserted under the slightly inclined condition between the left holding portion h' and the bottom plate portion b.sub.1 of the base portion b of the holder a. Then, a second part of the outer circumferential portion of the button battery l laid on the right holding portion h is depressed. As a result, the arm portion c and the arcuate wall e are elastically flexed outwardly as shown in FIG. 8B, and the second part of the outer circumferential portion of the button battery l is forced into the lower side of the right holding portion h. Then, the arm portion c and the arcuate wall e restore an original condition owing to their elasticity. In this manner, the button battery l is held in the accommodating space f of the holder a by the holding portions h and h', the bottom plate portion b.sub.1 of the base portion b, and the receiving plates g and g' as shown in FIG. 8C.
Thereafter, when the holder a holding the button battery 1 is inserted and mounted into the electronic equipment, a positive terminal (not shown) provided in the electronic equipment is brought into electric contact with the positive electrode surface 2a of the button battery l, and a negative terminal (not shown) provided in the electronic equipment is also brought into electric contact with the negative electrode surface 3a of the button battery l through a lower opening defined between the bottom plate portion b.sub.1 and the arcuate wall e.
In the above-mentioned holder a, however, even when the electrode surfaces 2a and 3a of the button battery l are incorrectly oriented, the button battery l can be inadvertently mounted into the accommodating space f of the holder a as shown in FIG. 9.
This is, correct orientation of the electrode surfaces 2a and 3a must be such that the positive electrode surface 2a is oriented upwardly, and the negative electrode surface 3a is oriented downwardly. However, even when this correct orientation is inverted, that is, even when the positive electrode surface 2a is oriented downwardly, and the negative electrode surface 3a is oriented upwardly, the button battery l is allowed to be mounted into the accommodating space f of the holder a by inserting one of the opposite parts of the outer circumferential portion of the button battery l and depressing the other part of the outer circumferential portion against the elastic force of the arm portion c and the arcuate wall e.
Accordingly, there is a possibility that a user takes no notice of such incorrect orientation of the electrode surfaces 2a and 3a of the button battery l upon mounting of the button battery l into the holder a, and that the user inadvertently inserts the holder a into the electronic equipment. As a result, the electronic equipment does not operate or malfunctions.